Desalt plant pilot run set for May

A decision has been made to conduct a pilot run of the Yuma Desalting Plant in May.

Lorri Gray-Lee, regional director of the Bureau of Reclamation’s Lower Colorado Region, announced Reclamation’s decision Monday to conduct the pilot run of the plant in collaboration with three water agencies from Arizona, California and Nevada.

The run has been under consideration for some time to test the idle plant’s capabilities and conserve Colorado River water.

The plant, west of Yuma, was essentially completed in 1992. Initial operational testing was conducted at about one-third capacity until early 1993, when it was stopped after flooding on the Gila River damaged a portion of the irrigation drainage canal.

Since then, the plant has operated only for a three-month demonstration run in 2007 at about 10 percent of capacity.

The pilot run will provide information about the plant’s capability to reliably produce water that could be used for a variety of purposes, conserve water stored in Lake Mead and help augment the river's water supply, Gray-Lee said.

“Drought, population growth and the continuing need for water in the Southwest have increased the demand on the Colorado River,” she said. “This collaborative undertaking is one more example of the ongoing state-federal partnership effort to address the drought’s impacts, conserve and stretch the river’s water supply and identify and secure additional supplies.”

The Metropolitan Water District of Southern California, the Southern Nevada Water Authority and the Central Arizona Project will provide about $14 million of the pilot run’s estimated $23.2 million cost.

“It would be very difficult for Reclamation to do a pilot run of the desalting plant without the funding and other support provided by these agencies,” Gray-Lee said. “That support allows Reclamation to operate the plant under the real-time conditions that are critical to obtaining the information necessary to help determine its operational readiness and long-term capabilities.”

About 21,700 acre-feet of desalted water will be produced during the pilot run. This water will be combined with 7,300 acre-feet of untreated irrigation drainage water and the total amount - 29,000 acre-feet - will be discharged into the Colorado River and included in deliveries to Mexico as required by treaty.

The state agencies will receive a water storage credit of one acre-foot of water in Lake Mead for each acre-foot of water conserved by the pilot run, based on each agency's funding contribution.

When first proposed, the planned pilot run raised concerns about its impact on the Cienega de Santa Clara Wetlands in Mexico that now receive the agriculture drainage water intended for use by the desalting plant.

As a result of binational consultations conducted with Mexico through the International Boundary and Water Commission regarding the pilot run, the U.S., Mexico and a binational coalition of nongovernmental organizations have each committed to arrange for the conveyance of 10,000 acre-feet of water to the Cienega.

The MWD, SNWA and CAP also will contribute funding for an environmental monitoring program for the wetlands that will begin prior to and conclude after the pilot run.  

Construction of the desalting plant was authorized by the Colorado River Basin Salinity Control Act of 1974. Its purpose was to desalt irrigation drainage water flows from the Wellton-Mohawk Irrigation and Drainage District so a portion of that water could be included in treaty-required deliveries of Colorado River water to Mexico. Since 1977, this drainage water has been conveyed from the district to the Cienega, bypassing the desalting plant.

At this time, Reclamation is not proposing to operate the plant beyond the pilot run, Gray-Lee said.

“Any decision about the plant’s future will be made after the pilot run is completed or terminated, and will be subject to and based upon appropriate compliance with federal law.”

An environmental assessment, funding agreement, joint report concerning U.S.-Mexico joint cooperative actions and other documentation related to this action are available on Reclamation’s Web site at www.usbr.gov/lc/yuma/environmental_docs/environ_docs.

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Joyce Lobeck can be reached at jlobeck@yumasun.com or 539-6853.